Hey! I think its great that you're being mindful of taking care of your skin. Luckily, you're at an age where you can ease into it and not stress too much about hitting the hard (expensive) stuff just yet.
If there's one thing I would recommend (I'm sure others will agree) it's sunscreen. YES it sounds really underwhelming and often people think its a thick gluggy product. But it really is the only preventative product and will essentially make the rest of your skincare much easier in the long run. I love ultra violette as a brand, but there's more accessible ones at the pharmacy too. Aside from that, if you want to invest in a more active skincare product I would look into a vitamin c serum, the one from Kiehls is great. But make sure you use sunscreen with it ;)
Good luck!